Systems have been designed to allow telephone subscribers to place calls directly, without the assistance of an attendant, after calling the main telephone number of a business. With the growing popularity of low cost DTMF (dual-tone multi-frequency) dial systems in the late 1970s and early 1980s, various solutions have been proposed to encode the dialed digits and then translate them to subscriber's names and refer callers to a database for a list of numbers served by the PBX (private branch exchange) of the called party.
The U.S. Pat. No. 4,608,460 to Carter is directed to such a system. Because a DTMF dial, however, is limited to twelve keys, a variety of translation schemes have been employed to make the translation. The end result, essentially, is always the same. The dialed digits represent an approximation of the alphabetically stored data for the intended party's name; and often this requires several attempts before the desired party can be located. If the directory of potential called parties is relatively limited, the system of Carter can be effective, and employs vocally conveyed information from a speech synthesizer relating the other subscriber to the caller; whereupon the caller selects the other subscriber (called party) in response to the vocally conveyed information to effect the connection.
In the U.S. Pat. No. 4,734,931 to Bourg, a distributed calling directory uses a computer interface to a central database to present the information to the calling party's computer terminal to assist with the dialing. This system is particularly useful by dedicated users, such as hotel desk managers, to look up information in order to intelligently process calls. The system, however, does not automatically provide inbound callers with the directory information.
An effort to resolve the problems associated with DTMF dialing is disclosed in the U.S. Pat. No. 4,979,206 to Padden. In the system of the Padden patent, a caller requesting directory assistance is connected to an automatic speech recognition unit, and is prompted to speak commands for identifying the requested directory number. A speech recognition unit in the system converts the received speech signals into data signals for searching a directory number database. If a directory listing is located, the number of that listing is announced to the calling party; and the calling party is prompted to speak a command indicating whether a call to that number should be established. Because of the wide variety of names and pronunciation of names which exist, the system of the Padden patent, and systems similar to it, are subject to shortcomings in accuracy, and often send callers to an attendant or operator because the required name did not appear on file through the spoken name.
A different approach is disclosed in the U.S. Pat. No. 5,850,433 to Rondeau. In the system of this patent, the video display of a personal computer is employed to provide an immediately visible directory reference from a computer server database. The computer user is then allowed to select the desired directory entry and to place a call to the intended party using a voice link over a second communications line, or an encoded voice stream directly to the personal computer. The approach used in the system of this patent, however, requires a separate computer database which often contains additional clutter, such as advertising, with no integration with the main telephone or employee directory of a business or other enterprise.
The U.S. Pat. No. 6,014,711 to Brown is directed to a voice over Internet identifier for a directory to allow voice messages to be sent to a recipient over an Internet mail connection when at least one unique identifier for the recipient is known, but when the electronic mail address of the recipient is unknown. The identifier used may be the telephone number of the recipient, which then is used by the system to translate the link to the e-mail address. The user then may complete the link by addressing the recipient at the e-mail address. Basically, the system of this patent is an information message to the calling party desiring to effect a voice connection over an e-mail address link.
Another approach is disclosed in the U.S. Pat. No. 5,999,609 to Nishimura. This patent is directed to a system for processing call requests through the telephone network, under the direction of the caller, who graphically manipulates the call through a graphical user interface on a personal computer. The system requires a personal computer display.
The U.S. Pat. No. 6,049,594 to Furman is directed to a system for automatic vocabulary generation for voice dialing. The system of this patent utilizes the storage of the record of the past calling records of each calling party to determine the called parties most likely to be called by this calling party. The voice recognition system then operates, first with the previously stored called parties to determine whether there is a match for any new call.
It is desirable to provide an on-line directory service for a business or enterprise which allows callers using either PCM telephones or IP telephones or computers to call others within the business or enterprise through access to an enterprise-wide database of directory information, including translation tables for communicating between PCM and IP devices.